The invention is concerned with a closing apparatus for a thermal printer. More particularly, this invention is concerned with the prevention of damage to the thermal printer due to an accidental opening of a cover, a falling of the printer or movements due to random vibrations.
Thermal printers generally include a fixed chassis portion and a cover associated with the chassis so that the cover and chassis together can enclose the printer. The fixed chassis portion is provided with all the printing devices, and fixed in its inside is a paper drive roll. A cover is provided to cover the various parts and with the chassis together provide for a complete closure.
In the printing art, these are known as apparatuses in connection with the closing method of the cover but up to the present there is no known solution to the problem of avoiding damage when the cover is opened and damage is caused.
The closing apparatus according to the invention permits a paper drive roll to be fixed inside the cover to position itself, when the printer is closed, the roll moves in a suitable roll housing seat that locks the paper drive roll so as to prevent the paper drive roll from getting out of the printer apparatus in case of accidental pushes.
The seat has a bottom wall which is positioned in the same direction of the closing apparatus both when the printer cover of the printer is opened and access to the printer is provided or when the printer cover is closed and when the printer cover is opened and is moved during operation in the roll rotation direction. This permits the cover to maintain the roll in a fixed position on the seat bottom due to the force exerted by the roll, during its rotation in a clockwise direction, which causes the creation of a downwards push which helps to block the paper drive roll in the roll housing seat. As the cover is closed or moved from its open position to its closed condition, the roll is moved from one end of the roll housing seat to the other end of the seat, so that when the cover is open, the roll may be rotated, and when the cover is closed the roll is locked in the seat.
When the cover is finally closed and in its closed condition, the printer is in standby condition and blockage of the printer is created, produced by the shape of the roll housing seat, that absolutely prevents the roll from exiting or going out from the seat and consequently, the roll housing seat and paper drive roll cooperate together to lock the printer cover to the chassis and prevent the printer cover from opening and exposing the printer.
The direction of movement of the paper drive roll in response to the direction of the moving force of the paper drive roll, which is parallel with the seat bottom, helps to generate a push that keeps the paper drive roll on the bottom and blocking it.
When the printing phase begins, the paper drive roll brings itself or moves itself into the printing position. In the printing position, a possible outside force (for example a printer falling, vibrations, pushes or other cause) can actuate the paper drive roll and, according to the invention, the paper drive roll and the bottom wall of the seat together oppose such outside force.
In the direction of opening or closing of the printer cover, the same seat wall for the paper roll. The moving force of the paper drive roll is parallel to the seat bottom wall, and the moving force of the paper drive roll generates a push that keeps the roll on the bottom wall of the seat and blocks the movement of the paper drive roll to prevent the cover from opening.
The last force to be generated by the rotation of the paper drive roll on itself keeps the cover locked.
Thermal rings are provided on a thermal print head. The paper on which printing is to take place is kept pressed between the thermal print head and the paper drive roll by the push actuated by the thermal rings of the thermal head on the paper.
The closing apparatus, is suitable for any kind of thermal printer with a fixed chassis portion.